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The Ways in which Corals May or May Not Adapt

To Climate Change/Global Warming

by

Paul W. Sammarco1

and

Kevin B. Strychar2

1Louisiana Universities Marine Consortium (LUMCON)Chauvin, LA, USA

2Annis Water Resources Institute/Grand Valley State University

Muskegon, MI, USA

Current Hermatypic Coral Temperature and Latitudinal Limits

(Gross, 1977)

Atmospheric COAtmospheric CO22 and Temperature and Temperature

Over the Past 160,000 YearsOver the Past 160,000 Years

© Brooks/Cole Publishing Company / ITP

1984

2002

Mt. Hood, OregonGlacier National Park

. 1910 – 150 glaciers

. 2004 – 30 glaciers, each reduced

by 2/3 in size

Glaciers – The Integrators of

Atmospheric Temperature

Climate Change / Global Warming

. Energy required to lift an apple to a table = One (1) Joule (J)

. 500 MW power plant produces 5 x 108 J per second

. Between 1960s and 1985-1994, between 10o-24o N lat.

- Pacific – increase of 1.79 x 108 J m-2 (Wong et al., 2001)

. Since the 1950s, our oceans have absorbed an extra 15 x 1022 J

. If warming ceased today, the temperature of the ocean would not begin to reverse until the year 2075 (Church, 2007).

EndosymbioticZooxanthellae

Present inHermatypic

Corals

http://www.ecotourism.ca/effectsofcoralbleaching.html

Reef Prior to Bleaching

www.cosmos.ne.jp/~kamiyama/full.htm

Reef During the Bleaching Process

www.cosmos.ne.jp~kamiyama/full.htm

1-2 Months after Bleaching

www.cosmos.ne.jp~kamiyama/full.htm

. 1979 - First recorded coral bleaching event

. 1998 - El Nino yr - 48% of reefs in the W. Indian Ocean suffered bleaching;

16% of the world’s reefs appeared to have died.

. 2002 - 60-95% of the 110,000 sq mi of the Great Barrier Reef bleached

. Many more events since this time

Coral Bleaching

Regions of bleaching over the past 25 years

Country reporting coral bleaching

Locations of major bleaching events

http://www.ncdc.noaa.gov/paleo/outreach/coral/sor/images/map7-large.gif

Experimentation with

Scleractinian Corals –

Great Barrier Reef

Programmed Cell Death

Apoptosis

. Series of biochemical events leading to characteristic cell morphology and death (incl. blebbing,

cell membrane changes, shrinkage, nuclear fragmentation, chromatin condensation, and c-DNA fragmentation.)

. e.g., Differentiation of human fingers and toes in development of a fetus.

Necrosis

. Premature death of cells caused by acute cellular injury by external factors, such as infection, toxins, or trauma.

. e.g., Necrotic tissue resulting from a recluse spider bite (LA).

Symbiodinium sp. cells in situwithin the coral Acropora hyacinthus

_Control_ _Experimentally Increased Temperature_

NormalCell

ApoptoticCell

NecroticCell

1 m 500 nm 500 nm

Morze KoralowePl.reeflex.net/tiere/a756_Favites_complanata.htm

Favites complanata(Faviidae)

Percentage (%)of Cells

F. complanata(Faviidae - coral)

Symbiodinium sp.(symbiont)

Time (hrs)

Favia complanataApoptotic Cells, Host vs. Symbiont

Normal

Necrotic Apoptotic

Contrary to popular Opinion

90% of the zooxanthellae in 90% of the zooxanthellae in bleaching corals have been found bleaching corals have been found

in various stages of cell deathin various stages of cell death

www.starfish.ch/c-invertebrates/corals.html

Acropora hyacinthus(Acroporidae)

Zoo2.zool.kyoto-u.ac.jp/~hirose/Marine/corals/porites.htm

Porites solida(Poritidae)

Similar Response to

Same Experimental Treatments

. Adaptation

- Requires natural selection by these temperature conditions in the evolutionary history of this group

. Exaptation

- Requires that some other physiological trait, previously existing, function known or unknown, serves to enhance temperature tolerance.

Adapatation or Exaptation in the Coral Hosts?

. Is this temperature adaptation / exaptation restricted to only the zooxanthellate scleractinian corals?

. Does it extend to other coelenterate groups?

www.korallenfarm.de/Weiche.htm

Sarcophyton ehrenbergi(Alcyoniidae)

Sarcophyton sp.

bleached

www.ratemyfishtank.com/friendemail.php/13611

28C30C

32C

34C

36C

34C

28-32C, 36C

Percentage (%)of Cells

Sarcophyton ehrenbergiNecrotic Cells

Sinularia lochmodes(Alcyoniidae)

David Robbwww.davidrobb.me.uk/Marine/Invertebrates.htm

Xenia elongata(Xeniidae)

Could this phenomenon regarding

endosymbiotic zooxanthellae and bleaching

apply to other cnidarians and other phyla

as well?

http://www.berghia.net/aiptasiaBiology.html

Aiptasia patella(Anthozoa, Actiniaria)

Aiptasia pallida, bleached

Jessie Kershnerwww.coralscience.org/main/articles/

symbiosis-3/aiptasia-a-bleaching

Cassiopeia xamachanaScyphozoa

Jonathan Dunderwww.freeinfosociety.com/site.php?postnum=833

http://www.oceanwideimages.com/Large-Image.asp?pID=15969&cID=73&rp=species%252Easp%253Fs%253DCassiopea%2Bxamachana%2526p%253D1

Ewa Barskacommons.wikimedia.org/wiki/File:Tridacna_gigas_by_Ewa_Barska.jpg

Tricacna gigas(Mollusca, Bivalvia)

Tricacna gigasBleaching

James W. Fathereewww.advancedaquarist.com/2010/8/inverts

. Zooxanthellae more sensitive to temperature than theirhosts in scleractinian corals

. Alcyonaceans - Similar to scleractinian corals

. Application to other cnidarians?

- Bleaching, yes

- Greater sensitivity in endosymbionts than hostMost likely.

. Application to zooxanthellate organisms from otherphyla?

- Most likely, yes.

Are there alternatives to endosymbiotic zooxanthellae?

And will they save the day?

Didemnum molle (Ascidea, Didemnidae)With symbiotic Prochloron didemni

http://university.uog.edu/botany/474/cyano/prochloron.html

Lissoclinum patella (Ascidea)with symbiotic cyanobacteria (e.g. Prochloron didemni)

www.eol.org/pages/65008

Spongilla lacustris (Porifera)with symbiotic Chlorella (Chlorophyceae)

Jim Novakwww.biolib.cz/en/image/id18059/

Potential Acquisition of Replacement Symbiontse.g., Prochloron or Chlorella

. Would require host to recognize new symbiont immunologically as “self”

. Would require symbiont to recognize new host immunologically as “self”

. Would require new symbiont to be adapted to reproduce inside host tissue, even if only asexually

. Host would have to be adapted to produce nutrients in concentrations acceptable to the symbiont

. Symbiont would have to be adapted to accept nutrients from host – in a balanced manner

Potential Acquisition of Replacement Symbiontse.g., Prochloron or Chlorella

. Symbiont would have to be adapted to produce O2 and sugars in the right concentrations for the host.

. Host would have to be able to accept O2 and sugars from the symbiont

. Host would have to be able to expel the new symbionts when there was an imbalance in resource transfer or symbiont mortality.

Has this ever happened before?

Yes.

Three precedents of replacement

http://www.nature.com/scitable/knowledge/library/the-rhizosphere-roots-soil-and-67500617

Ectomycorrhizal fungi replacing arbuscular mycorrhizal fungi on tree roots

https://theaphidroom.files.wordpress.com/2013/01/figure-1_mandrioli_manicardi.jpg

Yeasts replacing Buchnera bacteria in aphids

http://www.kurzweilai.net/how-to-synthesize-a-new-kind-of-yeast-cell-or-person

http://tolweb.org/onlinecontributors/app?service=external/ViewImageData&sp=30254

http://www.polypompholyx.com/wp-content/uploads/2013/05/endosymbiotic_matryoshka.png

Endosymbiotic algae replacing plastids in some peridinin dinoflagellates.

Could such a substitution happen again –

particularly in this case?

. Possible, but tall order.

. Imagine rolling this many dice simultaneously and hoping to come up with all of them yielding the right formula. . Probability exceedingly low.

http://www.dreamstime.com/stock-illustration-many-dice-large-group-showing-six-points-image42162002

Oceanic Climatic ZonesToday

http://www.waterencyclopedia.com/images/wsci_01_img0100.jpg

Poleward Migration of Oceanic Climatic Zones

Expansion of Tropical Zone; Movement of Sub-Tropical, Temperate, and Sub-Polar Zones; Compression of Polar Zones

Shrinking of

Arctic Polar Cap

and

Permafrost

Boundary

Maps.grida.no/go/graphic/shift-in-climatic-zones-arctic-scenario

http://www.cryofthewater.org/images/2.jpg

Predictions (cont.)

. Emergence of a “Hyper-Tropical Oceanic Climatic Zone”

. Decrease in species diversity of corals and other zooxanthellate organisms

- Due to species-specific sensitivity to increasing seawater temperatures

Possible Emergence of a Hyper-Tropical Zone

Possible introduction of new Hyper-Tropical Zone, and decrease in species of diversity of corals and

other zooxanthellate organisms therein

?

Predictions (cont.)

. No net gain in coral reef cover with time

- Increase in higher latitudes, but –

- High coral mortality in the warmer regions – lower latitudes

- Probably a decrease in species diversity overall, due to pushing corals to the limits of their distribution and mortality in the hyper-tropical zone.

http://www.ageekyworld.com/a-must-visit-place-great-barrier-reef/

Thank you

Predictions

. Latitudinal Expansion of Corals and other temperature- limited zooxanthellate organisms

- e.g., Acropora cervicornis off Broward County, FL

. Similar observations made in Japan

. Latitudinal limits due to light – PAR in winter?

. Adaptation of zooxanthellae for low light levels

- Mesophotic zones

- Deep-water on Jamaican deep reefs

- Probably acclimation to low light levels insufficientafter a point.

Amphiscolopslangerhansi

(Platyhelmenthes)

Nanozine.blogspot.com/2007_05_01_archive.html

Coral Bleaching Hotspots(8/27/05)

http://python2011.globalblogs.org/files/2011/10/dice.jpg

http://www.getting-positive-karma-now.com/about-the-Nirulas.html

Implications

Zooxanthellae occur in

hundreds of

marine invertebrate species

Similar Responses in the

Other two Alcyonacean Species

(with variance)

http://www.care2.com/causes/5-of-the-worlds-most-endangered-coral-reefs.html

Outline

I.Coral Reefs and Bleaching – Background

V. Predictions for Extinction of Zooxanthellate Organisms